Brillouin Scattering in Ethanol-Water Mixtures

Liquid water and liquid ethanol are both hydrogen-bonded. However, while water possesses a three dimensional hydrogen-bonded network, ethanol shows chain and ring association. Thus, investigation of mixtures of these two liquids are of considerable interest, in particular, when results are subsequently compared with those obtained for aqueous solutions of higher alcohols, where phase separation may be observed. Indeed, the anomalous negative excess entropy characteristic for aqueous mixtures of lower alcohols containing hydrophobic groups may be successfully discussed by invoking molecular-scale segregation of the components across the entire composition range [1].